#marspathfinder — Public Fediverse posts

To conclude our look at the Pathfinder mission, here are two mosaics of images from the lander of the area just to the north' The top one was made just after landing to check the rover egress site was safe. The ramp has not yet deployed, nor has the camera mast. The lander camera is just above the deck. In the second image the camera mast has raised the camera up higher. The main difference is the set of rover tracks.
#mars #marspathfinder

Now we must move on to a new topic...

To conclude our look at the Pathfinder mission, here are two mosaics of images from the lander of the area just to the north' The top one was made just after landing to check the rover egress site was safe. The ramp has not yet deployed, nor has the camera mast. The lander camera is just above the deck. In the second image the camera mast has raised the camera up higher. The main difference is the set of rover tracks.
#mars #marspathfinder

Now we must move on to a new topic...

... a 5 or 6 day drive with my family from work in Ontario to a summer vacation on Vancouver Island (where I am now). Every time we stopped for a meal I would look for the local paper (we had newspapers back then) to see the latest images. No internet on the road at the time. You youngsters don't know how good you have it! (Oh yeah - we had to walk 5 miles barefoot in the snow to get to school).
#mars #marspathfinder

... a 5 or 6 day drive with my family from work in Ontario to a summer vacation on Vancouver Island (where I am now). Every time we stopped for a meal I would look for the local paper (we had newspapers back then) to see the latest images. No internet on the road at the time. You youngsters don't know how good you have it! (Oh yeah - we had to walk 5 miles barefoot in the snow to get to school).
#mars #marspathfinder

Sojourner had 3 cameras - B/W stereo cameras in front and a colour camera at the rear. Here are a few images from the rover:

https://www-k12.atmos.washington.edu/k12/mars/graphics/81315_full.jpg

https://www-k12.atmos.washington.edu/k12/mars/graphics/81316_full.jpg

https://www-k12.atmos.washington.edu/k12/mars/graphics/81325_full.jpg

https://www-k12.atmos.washington.edu/k12/mars/graphics/81003_fu.jpg

https://www.andrew.cmu.edu/user/dc88/ops/81220_full.jpg

Most of them plus others from the lander are collected here:

https://www-k12.atmos.washington.edu/k12/mars/nasa_jpl_mpf_pics.html

Pathfinder in 1997 was the first big internet planetary mission. I was driving across the northern states at the time of landing...
#mars #marspathfinder

Sojourner had 3 cameras - B/W stereo cameras in front and a colour camera at the rear. Here are a few images from the rover:

https://www-k12.atmos.washington.edu/k12/mars/graphics/81315_full.jpg

https://www-k12.atmos.washington.edu/k12/mars/graphics/81316_full.jpg

https://www-k12.atmos.washington.edu/k12/mars/graphics/81325_full.jpg

https://www-k12.atmos.washington.edu/k12/mars/graphics/81003_fu.jpg

https://www.andrew.cmu.edu/user/dc88/ops/81220_full.jpg

Most of them plus others from the lander are collected here:

https://www-k12.atmos.washington.edu/k12/mars/nasa_jpl_mpf_pics.html

Pathfinder in 1997 was the first big internet planetary mission. I was driving across the northern states at the time of landing...
#mars #marspathfinder

Here is the suggested route for Sojourner if it had survived longer. The horizon is only a few tens of meters away, and Sojourner could not cross it and lose contact. It might have had a good closeup view or even APXS analysis of the big boulder Zaphod, and the team also hoped for a view of North Knob, a hill only partially visible from the lander, as shown in earlier maps in this set. Speaking of views... what about the rover's cameras?
#maps #mars #marspathfinder

Here is the suggested route for Sojourner if it had survived longer. The horizon is only a few tens of meters away, and Sojourner could not cross it and lose contact. It might have had a good closeup view or even APXS analysis of the big boulder Zaphod, and the team also hoped for a view of North Knob, a hill only partially visible from the lander, as shown in earlier maps in this set. Speaking of views... what about the rover's cameras?
#maps #mars #marspathfinder

What Sojourner needed was a close horizon with a clear path that does not drop into any hollows. If it lost contact it would wait for instructions. If none came it would backtrack until it was back in contact. It might have been possible to program it to push ahead until contact resumed, but that's dangerous - get stuck between rocks or too tilted and ground commands are essential to recover. There was one possible route... tomorrow!
#mars #marspathfinder

What Sojourner needed was a close horizon with a clear path that does not drop into any hollows. If it lost contact it would wait for instructions. If none came it would backtrack until it was back in contact. It might have been possible to program it to push ahead until contact resumed, but that's dangerous - get stuck between rocks or too tilted and ground commands are essential to recover. There was one possible route... tomorrow!
#mars #marspathfinder

Look at the northern half of the image in the previous post. Rocks are silhouetted against the sky. We don't see rocks on those distant features in the southern half. To the north the horizon is only a few hundred meters away, and might be in reach. But there's something else: the landscape is pocked with depressions like The Swale and West Swale on earlier maps. Sojourner can't go into them. It's so small it would lose contact easily.
#mars #marspathfinder

Look at the northern half of the image in the previous post. Rocks are silhouetted against the sky. We don't see rocks on those distant features in the southern half. To the north the horizon is only a few hundred meters away, and might be in reach. But there's something else: the landscape is pocked with depressions like The Swale and West Swale on earlier maps. Sojourner can't go into them. It's so small it would lose contact easily.
#mars #marspathfinder

The plan for Sojourner after leaving the Rock Garden was to drive back to the starting area near Yogi rock, roughly following its tracks. If it was still looking healthy the science team considered pushing out to the horizon to look at something new. But which way to go? This image, the panorama projected into a circle, gives us some ideas. Sojourner absolutely could not operate with any significant loss of radio contact - it had to remain visible from the lander.
#mars #marspathfinder

The plan for Sojourner after leaving the Rock Garden was to drive back to the starting area near Yogi rock, roughly following its tracks. If it was still looking healthy the science team considered pushing out to the horizon to look at something new. But which way to go? This image, the panorama projected into a circle, gives us some ideas. Sojourner absolutely could not operate with any significant loss of radio contact - it had to remain visible from the lander.
#mars #marspathfinder

Maybe that location is the final resting place of Sojourner. But suppose the mission had not ended when it did... what were people thinking about a longer extended mission for the rover? Tomorrow we will look at that question.
#mars #marspathfinder

Maybe that location is the final resting place of Sojourner. But suppose the mission had not ended when it did... what were people thinking about a longer extended mission for the rover? Tomorrow we will look at that question.
#mars #marspathfinder

Why do they think Sojourner might be there? It's from that HiRISE image. This image is also from that HiRISE page:

https://static.uahirise.org/images/2007/details/cut/MPFtopo_HiRISE_annot.jpg

It shows color-coded topography and identifies a few rocks. One object seen in the image does not correspond to a rock in the panorama, so they suggest it is the rover, stranded there waiting for a command from Earth. It's not easy to match the image with the panorama but this may be right.
#mars #marspathfinder

Why do they think Sojourner might be there? It's from that HiRISE image. This image is also from that HiRISE page:

https://static.uahirise.org/images/2007/details/cut/MPFtopo_HiRISE_annot.jpg

It shows color-coded topography and identifies a few rocks. One object seen in the image does not correspond to a rock in the panorama, so they suggest it is the rover, stranded there waiting for a command from Earth. It's not easy to match the image with the panorama but this may be right.
#mars #marspathfinder

We don't know what happened to Sojourner but we do have a clue. The HiRISE camera on Mars Reconnaissance Orbiter imaged the Pathfinder site early in its mission and in 2007 the camera team put out this release about the image:

https://www.uahirise.org/PSP_001890_1995

on that page is this image:

https://static.uahirise.org/images/2007/details/cut/manyrovers_half_annot_1lyr.jpg

It shows end of drive images of the rover, and it also shows a site labelled 'Sojourner?'. My map uses that location...
#mars #marspathfinder

We don't know what happened to Sojourner but we do have a clue. The HiRISE camera on Mars Reconnaissance Orbiter imaged the Pathfinder site early in its mission and in 2007 the camera team put out this release about the image:

https://www.uahirise.org/PSP_001890_1995

on that page is this image:

https://static.uahirise.org/images/2007/details/cut/manyrovers_half_annot_1lyr.jpg

It shows end of drive images of the rover, and it also shows a site labelled 'Sojourner?'. My map uses that location...
#mars #marspathfinder

The map I just posted has a white dot on it labelled 'Final position of Sojourner?' We will see where this comes from next. Sojourner was commanded from Earth (via the lander) but if it didn't hear anything for a while it was programmed to follow its path backwards to the area where it started. If it got stuck it would listen for further instructions, which never came after the lander died. So we don't know where it might have ended up. Or do we?
#mars #marspathfinder

The map I just posted has a white dot on it labelled 'Final position of Sojourner?' We will see where this comes from next. Sojourner was commanded from Earth (via the lander) but if it didn't hear anything for a while it was programmed to follow its path backwards to the area where it started. If it got stuck it would listen for further instructions, which never came after the lander died. So we don't know where it might have ended up. Or do we?
#mars #marspathfinder

This is the 4th and last part of the Sojourner route map. The plucky little rover was driven south to avoid a group of rocks, then north again where it got stuck propped up on some rocks as we saw earlier. Finally it moved down into the rock garden area and investigated several rocks. It was moving north when it stopped to analyze Chimp, and then the mission ended - or at least the lander's ability to transmit ended. What of the rover?
#maps #mars #marspathfinder

This is the 4th and last part of the Sojourner route map. The plucky little rover was driven south to avoid a group of rocks, then north again where it got stuck propped up on some rocks as we saw earlier. Finally it moved down into the rock garden area and investigated several rocks. It was moving north when it stopped to analyze Chimp, and then the mission ended - or at least the lander's ability to transmit ended. What of the rover?
#maps #mars #marspathfinder

Compare this with the map published at the time. Here the tracks and images of the rover make an uninterrupted path. I really don't know why this was not done at the time. What they had was good enough, but it didn't really tell the story of the rover mission very well. Next: onwards to the Rock Garden!
#mars #marspathfinder

Compare this with the map published at the time. Here the tracks and images of the rover make an uninterrupted path. I really don't know why this was not done at the time. What they had was good enough, but it didn't really tell the story of the rover mission very well. Next: onwards to the Rock Garden!
#mars #marspathfinder

Here is part 3 of the map. The rover was commanded to drive clockwise around the lander to get to the Rock Garden, where a variety of rocks might be available for analysis. On the way various detours were needed to avoid difficult rocks. Eventually it reached Mermaid (sometimes called Mermaid Dune, but technically it's a dust drift or ripple, not a sand dune) and scuffed it (S12 on sol 29). It backed off the drift and moved west and then south again.
#maps #mars #marspathfinder

Here is part 3 of the map. The rover was commanded to drive clockwise around the lander to get to the Rock Garden, where a variety of rocks might be available for analysis. On the way various detours were needed to avoid difficult rocks. Eventually it reached Mermaid (sometimes called Mermaid Dune, but technically it's a dust drift or ripple, not a sand dune) and scuffed it (S12 on sol 29). It backed off the drift and moved west and then south again.
#maps #mars #marspathfinder

No, I did not forget it. The APXS sensor was not deployed properly and data was taken basically of the atmosphere, not the surface (if anything was obtained at all). It was supposed to be on the rock Souffle. Details of all this are in the text of my book but we won't go into them here. Where did the sol 23 drive end? Tomorrow we are going to need a new map to show it.
#mars #marspathfinder

No, I did not forget it. The APXS sensor was not deployed properly and data was taken basically of the atmosphere, not the surface (if anything was obtained at all). It was supposed to be on the rock Souffle. Details of all this are in the text of my book but we won't go into them here. Where did the sol 23 drive end? Tomorrow we are going to need a new map to show it.
#mars #marspathfinder

The second part of the Sojourner route map covers the same area as the first part. Sojourner drove back to the area below the ramp for some more work Then on sol 23 it drove east, past Scooby Doo and out of the right edge of the map. I separated these activities from the previous set for clarity, showing the older path faintly to tie the two together. What about APXS measurement A11? I don't show where the sensor was placed. Did I just forget to show it?
#maps #mars #marspathfinder

The second part of the Sojourner route map covers the same area as the first part. Sojourner drove back to the area below the ramp for some more work Then on sol 23 it drove east, past Scooby Doo and out of the right edge of the map. I separated these activities from the previous set for clarity, showing the older path faintly to tie the two together. What about APXS measurement A11? I don't show where the sensor was placed. Did I just forget to show it?
#maps #mars #marspathfinder

Just off the ramp on sol 2 we see a text box saying 'sol 2: A2'. The black dot shows the location of the end of the drive on that sol, and we learn that the second APXS measurement was made there (A1 was a test on the lander). Just above it a small box is also labelled A2 - that is the actual location of the sensor, so it was a soil measurement. A3 was on a rock. Keep in mind the rover is bigger than those dots! They took 2 attempts to get one on Yogi.
#mars #marspathfinder

Just off the ramp on sol 2 we see a text box saying 'sol 2: A2'. The black dot shows the location of the end of the drive on that sol, and we learn that the second APXS measurement was made there (A1 was a test on the lander). Just above it a small box is also labelled A2 - that is the actual location of the sensor, so it was a soil measurement. A3 was on a rock. Keep in mind the rover is bigger than those dots! They took 2 attempts to get one on Yogi.
#mars #marspathfinder

This is the first section of the Sojourner rover's route map. The lander bounced and rolled across the surface until it came to rest. It deflated its airbags and unfolded - the airbags are still visible around the lander base. On sol 1 Sojourner was on the lander. On sol 2 it drove off, and here we can follow it across the surface. Its APXS instrument was on a short arm which could be rotated down to touch the target - soil or rock (A1, A2 and so on).
#maps #mars #marspathfinder

This is the first section of the Sojourner rover's route map. The lander bounced and rolled across the surface until it came to rest. It deflated its airbags and unfolded - the airbags are still visible around the lander base. On sol 1 Sojourner was on the lander. On sol 2 it drove off, and here we can follow it across the surface. Its APXS instrument was on a short arm which could be rotated down to touch the target - soil or rock (A1, A2 and so on).
#maps #mars #marspathfinder

This set of images concludes our coverage of Sojourner's adventures. It's a pretty good way to tell the story, I think. If several images of the rover were taken in one sol, they are combined in one image. If only one image was taken it is the end of drive image.

OK - now let's start putting this on a map. The map of the site I showed earlier with all the rock names will be the base image, but enlarged and covered in several sections.
#mars #marspathfinder

This set of images concludes our coverage of Sojourner's adventures. It's a pretty good way to tell the story, I think. If several images of the rover were taken in one sol, they are combined in one image. If only one image was taken it is the end of drive image.

OK - now let's start putting this on a map. The map of the site I showed earlier with all the rock names will be the base image, but enlarged and covered in several sections.
#mars #marspathfinder

This is the 4th set of Sojourner rover images, taking us from sol 37 to sol 60. In the middle of the sequence the rover got itself in a very awkward position up on some rocks, and it took some considerable care and expertise to get it off safely. The T for technology tests were a variety of driving and maneuverability tests. The point here is, as you can see, they made the most of this little rover.
#mars #marspathfinder

This is the 4th set of Sojourner rover images, taking us from sol 37 to sol 60. In the middle of the sequence the rover got itself in a very awkward position up on some rocks, and it took some considerable care and expertise to get it off safely. The T for technology tests were a variety of driving and maneuverability tests. The point here is, as you can see, they made the most of this little rover.
#mars #marspathfinder

Sol 29 in that image has an asterisk to indicate that the activity took place on sol 29 but the images were taken on sol 30. I found I could work with these images and the map we saw earlier to put the rover locations and route unambiguously on a map, improving on what could be done at the time. We will get to that after the next 2 pages of these rover images.
#mars #marspathfinder

Sol 29 in that image has an asterisk to indicate that the activity took place on sol 29 but the images were taken on sol 30. I found I could work with these images and the map we saw earlier to put the rover locations and route unambiguously on a map, improving on what could be done at the time. We will get to that after the next 2 pages of these rover images.
#mars #marspathfinder

Sojourner's sols 24-36 in the same format. I made the rover stand out by increasing contrast relative to the rest of each image. For scale in these figures, Sojourner is 63 cm long, 48 cm wide and 28 cm high. W denotes wheel abrasion experiments, which involved rotating just the right middle wheel of the rover. It carried nickel, platinum and aluminum plates. As the wheel turned the amount of wear was estimated from changes in reflectivity measured by a light sensor.
#mars #marspathfinder

Sojourner's sols 24-36 in the same format. I made the rover stand out by increasing contrast relative to the rest of each image. For scale in these figures, Sojourner is 63 cm long, 48 cm wide and 28 cm high. W denotes wheel abrasion experiments, which involved rotating just the right middle wheel of the rover. It carried nickel, platinum and aluminum plates. As the wheel turned the amount of wear was estimated from changes in reflectivity measured by a light sensor.
#mars #marspathfinder

Here is the next section of the Pathfinder mission story - What Sojourner did between sols 15 and 23. These panels show motions and annotations indicate where various experiments were made. Soil mechanics experiments involved keeping 5 wheels fixed and rotation the sixth to estimate how hard the surface was. APXS measured composition. We will look at more measurements later.
#mars #marspathfinder

Here is the next section of the Pathfinder mission story - What Sojourner did between sols 15 and 23. These panels show motions and annotations indicate where various experiments were made. Soil mechanics experiments involved keeping 5 wheels fixed and rotation the sixth to estimate how hard the surface was. APXS measured composition. We will look at more measurements later.
#mars #marspathfinder

Pathfinder didn't just image tracks, it also imaged the rover itself, and here it was much more systematic. I started to put together sets of images to document sol by sol movements, to help with the mapping, and then realized just how useful it was to document the rover's activities like this. Here's the first page of images, like a storyboard for the mission. I will be doing this soon, I hope, for rovers on CLPS landers on the Moon.
#mars #marspathfinder

Pathfinder didn't just image tracks, it also imaged the rover itself, and here it was much more systematic. I started to put together sets of images to document sol by sol movements, to help with the mapping, and then realized just how useful it was to document the rover's activities like this. Here's the first page of images, like a storyboard for the mission. I will be doing this soon, I hope, for rovers on CLPS landers on the Moon.
#mars #marspathfinder

And here is a very quick and dirty reprojection of it into a very crude map, not controlled properly but just to show what it might look like.
#maps #mars #marspathfinder

And here is a very quick and dirty reprojection of it into a very crude map, not controlled properly but just to show what it might look like.
#maps #mars #marspathfinder

Here is a version reduced in size but with tracks highlighted in orange - I just made this very quickly now for this post so it is sketchy, but it is a start. Not really a lot better than that JGR map! I could have just projected this onto my map but I didn't, i used it as a guide for what follows.
#mars #marspathfinder

Here is a version reduced in size but with tracks highlighted in orange - I just made this very quickly now for this post so it is sketchy, but it is a start. Not really a lot better than that JGR map! I could have just projected this onto my map but I didn't, i used it as a guide for what follows.
#mars #marspathfinder

My first step was to take one of the panoramas the mission team released and paste onto it every image from the lander camera which showed tracks. This is not a perfect record: some bits of track were not imaged, if the wheels were on rocks they didn't leave tracks, and in the south they were too far away to show clearly. But it's a start. Here is that panorama . You have to look closely at a full size version to see the tracks.
#mars #marspathfinder

My first step was to take one of the panoramas the mission team released and paste onto it every image from the lander camera which showed tracks. This is not a perfect record: some bits of track were not imaged, if the wheels were on rocks they didn't leave tracks, and in the south they were too far away to show clearly. But it's a start. Here is that panorama . You have to look closely at a full size version to see the tracks.
#mars #marspathfinder

Why the gaps? They are caused by dead reckoning errors which built up during each drive, followed by a reset position based on post-drive imaging. But instead of correcting the faulty path to bring it to the right place, the map was just left with these gaps. I resolved to do better. There was a second map in that paper:

https://www.jpl.nasa.gov/images/pia01238-mars-pathfinder-rover-traverse-image/

Which looks much better but is not in a standard map geometry (i.e. you can't measure the lengths of its drives).
#mars #marspathfinder

Why the gaps? They are caused by dead reckoning errors which built up during each drive, followed by a reset position based on post-drive imaging. But instead of correcting the faulty path to bring it to the right place, the map was just left with these gaps. I resolved to do better. There was a second map in that paper:

https://www.jpl.nasa.gov/images/pia01238-mars-pathfinder-rover-traverse-image/

Which looks much better but is not in a standard map geometry (i.e. you can't measure the lengths of its drives).
#mars #marspathfinder

This map is from the summary paper by Matt Golombek et al.:

Golombek et al., 1999. Overview of the Mars Pathfinder Mission: Launch through landing, surface operations, data sets, and science results. JGR Planets, 104(E4), pp.8523-8553.

It is here: https://agupubs.onlinelibrary.wiley.com/doi/pdfdirect/10.1029/98JE02554

(I hope everyone can get it, I think it's open now).

The rover route is mapped but it is discontinuous. The figure caption in the paper explains it...
#maps #mars #marspathfinder

This map is from the summary paper by Matt Golombek et al.:

Golombek et al., 1999. Overview of the Mars Pathfinder Mission: Launch through landing, surface operations, data sets, and science results. JGR Planets, 104(E4), pp.8523-8553.

It is here: https://agupubs.onlinelibrary.wiley.com/doi/pdfdirect/10.1029/98JE02554

(I hope everyone can get it, I think it's open now).

The rover route is mapped but it is discontinuous. The figure caption in the paper explains it...
#maps #mars #marspathfinder

Now we have a map which can be used to trace the route of the little rover, Sojourner. The boundaries of that map are set to encompass the entire path followed by the rover. Before we start looking at this, let's see how the rover route was mapped at the time of the mission. Tomorrow!
#mars #marspathfinder

Now we have a map which can be used to trace the route of the little rover, Sojourner. The boundaries of that map are set to encompass the entire path followed by the rover. Before we start looking at this, let's see how the rover route was mapped at the time of the mission. Tomorrow!
#mars #marspathfinder